Caibons fob incandescent lamps



(No Model.)

v H. s. MAXIM. PROO'B SS 0F MANUFAGTURING GARBONS FOR INGANDESGENT LAMPSNo. 277,846. Patented May 15,1883.

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UNITED STATES PATENT OFFICE.

HIRAM S, MAXIM, OF PARIS, FRANCE.

PROCESS OF MANUFACTURING CARBONS FOR INCANDESCENT LAMPS.

SPECIFICATION forming part of Letters Patent No. 277,846, dated May 15,1883,

Application filed January 11, 1883. (No model.) i

To all whom it may concern:

Be it known that I, HIRAM S. MAXIM, a citizen of the United States, atpresent residing in Paris, in the Republic of France, have inventedcertain new and useful Improvements in the Process of ManufacturingGarbons for Incandescent Lamps, of which the following is a full, clear,and exact description.

My invention relates to processes of manufacturing carbon conductors forincandescent lamps from paper orsimilar fibrous materials. The usualprocess, aside from my improvements, is as follows: From paper, ormaterial of a similar texture or character-such as woodstrips or sheetsof the desired dimensions are formed. From these blanks approximating inshape to the finished conductors, though nearly a third larger, are cutor punched by means of a die. The blanks are thenlaid between sheets ofcard-board, packed in a muffle, and carbonized at a high temperature,after which they may be subjected to various treatments, or mounted atonce and inserted in the lamp. That portion of the process involving thepunching or cutting out of the blanks by dies or similar means isattended with many difficulties, mainly on account of the fibroustexture of the material employed and the difficulty met with in keepingthe cutting-edges of the dies in good order. With the most perfectappliances it is hard to produce a large number of blanks of exactly thesame character or free from frayed edges. it has been attempted toremedy this by first carbonizing the paper and cutting out theconductors from the carbonized sheets; but this process is attended bymany obvious objections, mainly arising from the brittle nature of thecarbon.

My improvements consist in partially carbonizing the sheets of fibrousmaterial, andv preferably under high pressure, as a preliminary tocutting out the blanks. By this treatment the material is brought to acondition midway between flexibility and brittleness, and is renderedvery dense-a condition which renders it far more suitable for undergoingthe subsequent steps in the process.

The method,in detail, will now be described,

I reference being had for this purpose to the accompanying drawings,where- Figure 1 represents a sheet of fibrous material inclosed betweensheets or plates of metal or carbon. Fig. 2 shows in elevation a pressfor keeping the sheets under pressure while undergoing the baking orpartial carbonization process.

The sheets of paper or other material, A, are laidbetweeu metal, carbon,or similar plates, B. A number of these are built up in a pile and putunder a press, 0. While in this condition a gas-flame is directedagainst the pile, and the pressure maintained as high as possible. Theyare heated until they have been exposed for a short time to atemperature about as high as that of melted lead. When they are removedthey should present a baked or partially-carbonized appearance-should bevery smooth to the touch and somewhat brittle. From them the conductorsare manufactured in the manner above described, or'in any other that issubstantially similar.

I would state that the special method of heating the fibrous sheets maybe greatly varied, so that, without confining myself to the specificmeans described,

What I claim is- 1. The improvement in the process of manufacturingcarbon conductors for incandescent lamps from sheets or strips offibrous material, which consists in baking or partially carbonizing thesaid sheets or strips before cutting the blanks therefrom, as and forthe purpose set forth.

factoring carbon conductors for incandescent lamps from sheets or stripsof fibrous material, which consists in baking or partially carbonizingthe said strips or sheets under pressure before cutting the blankstherefrom, as and for the purpose set forth.

In testimony whereof I have hereunto set my hand this 26th day ofDecember, 1882.

HIRAM S. MAXIM.

Witnesses:

R0121. M. HOOPER, DAVID T. S. FULLER.

2. The improvement in the process of manu-

